It is commonplace today for commercial video broadcast systems to have user-selected programming in which the user may select a desired program or programs from a collection or menu of program options. The individual program subscription or "pay-per-view" services offered by many commercial broadcast cable companies are examples of systems having user-selected programming.
Video playback systems for providing such user-selected programming typically include a plurality of video cassette recorder decks (VCRs). Commonly, one VCR is provided for each program offered. Each VCR is coupled at its output to a multiplexer which multiplexes the video signals outputted by the respective VCRs onto a broadcast medium such as a coaxial transmission cable. The VCRs play back their respective programs at predetermined times and time intervals. A subscriber who wishes to view a particular program merely selects the program and starting time from the available options. The broadcast system then codes the broadcasted signal so that the program is provided on the subscriber's television (TV). From the user's perspective, these systems ideally offer a large selection of programs, with each program being offered at frequent start times so that the maximum wait time for the start of the program is short.
The most widely used commercially-available VCR playback systems have been limited in that each VCR is capable of playing back only one program at a time. Therefore, one VCR is required for each channel on which programming is to be offered. Multi-channel programming often is a commercial necessity, which has meant that the system must include several VCRs. This has been disadvantageous both in terms of the cost of the VCRs and in terms of the logistics of system operation.
These commercial systems also have been limited because each channel must have idle times when the recording tape is being rewound. During rewinding, programming from the tape cannot be played back. For example, a system that broadcasts a particular 90-minute program and that takes five minutes to rewind can play back that program on a given channel no more frequently than every 95 minutes.